#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <assert.h>

size_t my_strlen3(const char* str) {
	assert(str);
	char* p = str;
	while (*str)
		str++;
	return str - p;
}

int main() {
	char arr[] = "abcdef";
	printf("%zu", my_strlen3(arr));
}